Advertising auctions are generally employed to select an advertisement to present to a user, for example, within an electronic document (e.g., a web page) served by a content server to a user device. Because the advertising opportunities (requests for advertisement bids to display an ad to a visitor on a website) outnumber the available budget, bidding on every request results in exhausting the budget quite early in the day resulting in bid opportunities being missed during later hours of the day that could potentially lead to conversions. As such, proportional allocation or pacing of advertisement spend across a time duration is frequently used in an effort to optimize the advertisement opportunities such that the advertiser does not miss out on requests during the later hours that could potentially lead to conversions. When advertisement traffic fluctuates, however, such proportional spend pacing can result in advertisement overspend or underspend.